The symptoms of pregnancy are definitely different from those of menstruation, which is a normal physiological phenomenon, and pregnancy is also a normal physiological phenomenon, but after pregnancy, under the effect of estrogen, the corresponding symptoms will appear. Since a thousandfold increase in estrogen causes water and sodium retention, mild edema of the mucous membrane of the gastrointestinal tract occurs, which is reflected clinically in nausea, vomiting, anorexia or drooling, which are symptoms of pregnancy. In addition, pregnancy is also associated with breast enlargement, mild pain, and coloring of the nipples and areolas in the presence of estrogen. When you have your period, you may experience breast tenderness before your period, but your breasts are not as soft to the touch and your nipples and areolas are not colored. There is no nausea or vomiting when menstruation occurs, except in cases of severe clinical dysmenorrhea that causes nausea and vomiting.